1. Field of the Invention
The invention relates generally to semiconductor-on-insulator substrates, and semiconductor structures within and upon semiconductor-on-insulator substrates. More particularly, the invention relates to multiple order radio frequency harmonic suppression within radio frequency circuits comprising semiconductor structures within and upon semiconductor-on-insulator substrates.
2. Description of the Related Art
Semiconductor structures include semiconductor substrates within and upon which are formed semiconductor devices such as but not limited to resistors, transistors, diodes and capacitors. The semiconductor devices are connected and interconnected using patterned conductor layers that are separated by dielectric layers.
Within the context of semiconductor substrates that are used in the fabrication of semiconductor structures, there has more recently evolved the use of semiconductor-on-insulator substrates in comparison with the use of bulk semiconductor substrates. Semiconductor-on-insulator substrates comprise a base semiconductor substrate, a buried dielectric layer located upon the base semiconductor substrate and a surface semiconductor layer located further upon the buried dielectric layer. Thus, under circumstances where a base semiconductor substrate and a surface semiconductor layer within a semiconductor-on-insulator substrate comprise a single semiconductor material having a single crystallographic orientation, the semiconductor-on-insulator substrate may under certain circumstances be fabricated by incorporation of a buried dielectric layer within a thickness of a bulk semiconductor substrate.
Semiconductor-on-insulator substrates find many uses within semiconductor structure fabrication, and more recently semiconductor-on-insulator substrates have been proposed for fabrication of complementary metal oxide semiconductor (CMOS) structures for use within radio frequency applications. Semiconductor-on-insulator substrates are desirable within such radio frequency applications insofar as the presence of the buried dielectric layer provides for reduced capacitive coupling between a surface semiconductor layer and a base semiconductor substrate within the semiconductor-on-insulator substrate.
A performance characteristic that is desirable within radio frequency integrated circuit applications is that a multiple order radio frequency harmonic with respect to a primary transmitted radio frequency power frequency (i.e., 1fo), such as but not limited to a second order harmonic (i.e., 2fo) or a third order harmonic (i.e., 3fo), be considerably suppressed (i.e., from at least 30 to 40 decibels (dB) suppressed). Unfortunately, current configurations of semiconductor-on-insulator substrates typically do not fulfill the forgoing desirable multiple order radio frequency harmonic suppression characteristics.
Thus, desirable are semiconductor-on-insulator substrates and related semiconductor structures, and methods for fabricating the semiconductor-on-insulator substrates and related semiconductor structures, that allow for fabrication of radio frequency devices and radio frequency circuits with suppressed multiple order radio frequency harmonics.